According to a new study, taking calcium supplements might increase an elderly woman’s chances of dementia. This risk is greatly increased if the woman has suffered from a cerebrovascular disease such as a stroke. In the study, the researchers looked at the medical history of 700 women between ages 70 and 92 who did not have dementia at the start of the study. The researchers found that 54 women had had a stroke before the study started, and 98 women were taking calcium supplements at the start of the study.
This research, which was started in 2000 and conducted over the next five years, concluded that the women who had previously had a stroke and who regularly took calcium supplements at the start of the study were seven times more likely to develop dementia over the five-year period, compared to women who had a stroke but who did not take calcium supplements.
Furthermore, the researchers found that women who had signs of a disorder that affects blood flow in the brain and regularly took calcium supplements were twice as likely to develop dementia over five years as women who had signs of this disorder but did not take those supplements. The results were published in the journal Neurology.
The study participants took a variety of tests at the beginning and end of the study, including memory tests and tests to judge thinking skills. Researchers also conducted CT brain scans on 447 participants at the start of the study, which revealed that 71% of these women had white matter lesions.
A total of 98 women were taking calcium supplements at the start of the study, and 54 women had already experienced a stroke. During the study, 54 more women had strokes and another 59 women developed dementia.
Of the women with a history of stroke who took calcium supplements, six out of 15 (40%) of them developed dementia, compared with 12 out of 93 (12.9%) women with a history of stroke who did not take supplements. Among the 83 women who took calcium supplements with no history of stroke, 18 of them developed dementia (21.6%), compared with 33 out of the 509 who did not take supplements (6.4%).
One important thing to note, however, is that there is indeed a link of dementia with increased use of calcium supplements, but according to Dr Silke Kern, a neuroscience researcher at the University of Gothenburg in Sweden, and the study’s lead coauthor, this link does not prove that taking calcium supplements causes dementia. Dr Kern said, “Women with cerebrovascular disease and osteoporosis should discuss this new information with their clinicians.” Kern noted that some guidelines have recommended that seniors consume 1,000 to 1,200 milligrams of calcium a day to prevent osteoporosis.
Another important distinction that Kern made was that the risk was only carried by calcium supplements but calcium from natural sources such as diet, including milk and eggs, did not increase the risk. The risk of stroke might be due to the fact that excess calcium in blood can cause calcium score, the phenomenon of calcium plaque getting stuck in artery walls, which is an early sign of coronary artery disease and usually precedes the development of actual blockages.
Kern says she isn’t 100% sure as to why exactly calcium supplements may have such an adverse effect. Another important thing to note is that the results of the study cannot be comprehensively and accurately extrapolated to the actual population, hence future studies need to be conducted, preferably with bigger study population to fully understand the link between calcium supplements and cerebrovascular diseases.
Controversy Surrounding Calcium
There’s a lot of controversy surrounding calcium. One study was published in BMJ in 2015 in which researchers examined the effects of calcium intake on bone density and risk of fracture in adults over age 50. There were only two eligible randomized controlled trials of dietary sources of calcium, but there are 50 reports from 44 studies about the interlinked relationship between dietary calcium, milk, or dairy intake and fracture outcomes.
For dietary calcium, most studies reported no association between calcium intake and fracture. For milk and dairy intake, the results were same. Most studies reported no association. In 26 randomized controlled trials, calcium supplements reduced the risk of total fracture and vertebral fractures but not hip or forearm fracture. Only one trial in frail elderly women in residential care with low dietary calcium intake and vitamin D concentrations showed significant reductions in risk of fracture.
The results proved that dietary calcium intake is not linked with the risk of fracture, and there is no evidence that increasing calcium intake from dietary sources prevents fractures. However, evidence that calcium supplements prevent fractures is unreliable and erratic.